Cabinet ministers expect another heavy defeat for Theresa May’s Brexit deal when the Commons votes again next week after the UK walked away empty-handed from the latest negotiations with Brussels.

Talks between EU negotiators and Attorney General Geoffrey Cox ended in deadlock yesterday after Brussels refused to grant assurances over the Irish backstop.

The backstop has proved the biggest obstacle to Mrs May’s efforts to persuade her Tory colleagues to back her Brexit deal.

But Europe refused to make changes to the withdrawal deal which would allow Cox to issue new legal advice saying that the backstop will not last indefinitely.

The impasse means the PM is running out of time to secure changes before the Commons votes again on Tuesday.

Ministers have resigned themselves to defeat with one believing she is ‘certain’ to lose again following her record 230-vote defeat in January.

Some of her Tory colleagues believe the majority against her deal could be as high as 100 this time, it is claimed.

Michel Barnier, the EU’s chief negotiator, gave a gloomy assessment of the talks but said afterwards that he was ‘still determined’.

EU officials are preparing to work round the clock this weekend, saying it is ‘unlikely’ an agreement will be reached before then and that talks will go down to the wire.

‘There’s no sign of a breakthrough and there will need to be some tough work in the days ahead if there’s going to be deal,’ one EU official said, adding that it was still possible negotiators could seal a deal by the end of the weekend.

But that would leave Mrs May just 24 hours to travel to Brussels to endorse the deal on Monday before taking it back to be voted on by MPs the next day.

Tory Brexiteers have already warned the Prime Minister they want at least two days to scrutinise any new offer and will not be ‘bounced’ into an early vote.

Mr Cox, who met Mr Barnier with Brexit Secretary Stephen Barclay, described Tuesday’s late-night talks as ‘robust’ as he returned to London yesterday.

He said: ‘We are into the meat of the matter now. We’ve put forward some proposals, very reasonable proposals, and we’re now really into the detail of the discussions.

‘Both sides have exchanged robust, strong views and we are now facing the real discussions. Talks will be resuming soon.’

Last night it emerged that Mr Cox is trying to secure an ‘arbitration panel’ that would determine if the two sides were acting in good faith in trying to find alternatives to the backstop.

But according to a report on the BuzzFeed website, the idea was rejected by Mr Barnier.

Sources say Mr Cox and Mr Barclay could be back in Brussels as early as tomorrow to help push a deal over the line in time for next week’s vote.

Technical discussions, led by Mrs May’s chief Brexit adviser Olly Robbins, will continue in Brussels. Neither side is said to have presented any new formal text. The latest row over the backstop – designed to prevent a hard border emerging in Ireland – centres around disagreements over language which could either form a new document to be added to the Withdrawal Treaty or sit alongside it. According to EU sources, ‘inspiration’ for the text has been drawn from a joint letter sent to Mrs May by EU Commission and Council chiefs Jean-Claude Juncker and Donald Tusk in January.

This included a pledge to reach a future trade agreement ‘speedily’ and talked of a ‘firm determination’ to have an alternative to the backstop ready so it would either never have to be used or only triggered ‘temporarily’.

Negotiators are struggling with the ‘semantic’ challenge of agreeing on a form of words which will please both sides.

Downing Street acknowledged the talks were deadlocked but insisted they would continue.

A spokesman for the Prime Minister said: ‘The EU continues to say they want this resolved and they want the UK to leave with a deal. Parliament has been clear we need legally-binding changes to ensure the UK cannot be stuck in the backstop indefinitely.’

An EU Commission spokesman said: ‘While the talks were held under a constructive atmosphere, discussions have been difficult and we have not yet been able to identify any solution.’

Meanwhile, EU boats will be banned from fishing in UK waters if Britain leaves without a deal under a new law to be laid before Parliament today.

Environment Secretary Michael Gove will say boats which want to fish off the UK coast will need a licence from the Government.

MPs were warned last night they may lose their Easter holiday to push through Brexit legislation. It was the clearest hint yet that Brexit is set to be delayed.

Mr Gove warned MPs that votes on vital Brexit legislation could be held during Easter.